Continuous casting process



March 17, 1942. s. JUNGHANS CONTINUOUS CASTING PROCESS Filed Feb. 18,1939 W h u r Jw f. A da% .8 lh L Patented Mar. 17, 1942 CONTINUOUSCASTING PROCESS Siegfried Junghans, Stuttgart, Germany, assignor toIrving Rossi, New York, N. Y.

Application February 18, 1939, Serial No. 257,222 In Germany February18, 1938 10 Claims.

The continuous casting processes which have been developed recentlyenable endless castings to be produced in one uninterrupted continuousoperation, i. e. without interrupting the casting process. Thesecastings may be in form of round rods or bars, squares, or plates ofrectangular cross section. A proposal has also been made to producesimilar hollow bodies by the continuous casting process.

It is the object of the present invention to produce such endlesscastings with varying cross sections in a continuous casting process,so-that one and the same endless casting possesses different crosssections at various points throughout its length. These changes in thecross section may be made according to requirements either abruptly soas to form sharp shoulders or the change may be gradualin the manner ofa cone. Various practicable methods are required according to thevariation in cross section it is desired to obtain and these methodswill be described hereinafter.

The accompanying drawing illustrates by way of example suitable devicesaccording to the invention in which:

Figure 1 illustrates the arrangement of several moulds for castingcastings having stepped cylindrical cross sections,

Figure 2 illustrates another arrangement of the mould for obtainingcastings according to the device illustrated in Figure 1,

Figure 3 illustrates an arrangement of the mould for casting endlessconical castings,

Figure 4 illustrates an arrangement for producing castings according toFigure 3 as used in a continuous casting process, wherein the mouldcarries out a continuous up and down movement during the castingprocess.

Figure 5 illustrates an arrangement of the mould whereby two castingscan be cast simultaneously, one surface of each casting extendingparallel to the direction of feed thereof whilst the other surface isconical.

Figure 6 illustrates a mould arrangement according to Figure 5 for acasting process wherein themculd is continuously moved up and downduring the casting process.

In all the figures a is the nozzle used in continuous casting processesfor c nveying the molten mass into the mould. The end of this nozzle isdesignat d by b and it is intended that this end sheuld always beimmersed in the liquid head of the casting being produced in the mould.

According to the device illustrated with reference to Figure 1, variousmoulds, c, d, e, j .are provided, these being arranged in the manner oftelescopic tube at the beginning of the casting process. As will be seenthe mould possesses a number of difi'erent cross sections, eachindividual section being arranged so that it may be separately removedin the downward direction. The arrangement may also however, be suchthat each section can be separately removed in the upward direction. Theinlet and outlet pipes for conveying cooling medium to the mould aredesignated by g h, i, k. The upper ends of each section of the mould areinternally bevelled, so that the transition from one cross section tothe next cross section of the mould extends along the said bevellededges.

The casting process by means of the arrangement according to Figure 1 isas follows:

At the beginning of the casting process the lower end I) of the fillernozzle a extends into the inner mould f a depth such that when the mouldis filled and the casting plant has been adjusted to correct positionsaid lower end I: is constantly located within the liquid head in themould f. Any desired length of casting may then be cast by means of thismould j the setting metal being withdrawn in the downward direction asis known in continuous casting processes. When the desired length ofcasting having the cross section of the mould f has been cast, the mouldis pulled downwardly while the casting process continues. During thewithdrawal of the mould f, the liquid head, the height of which ispreferably maintained at a constant level, gradually fills the bevelledportion of the mould ,f and when the latter has been completely removedthe liquid head reaches'the wall of the mould e. The desired length ofcasting having the cross section of e is then cast in the cast in themould c. When it is desired to proceed to the cross section d the moulde is pulled downwardly and the same procedure is followed as whenproceeding from the mould f to the mould e. The procedure is the samewhen the casting is to be enlarged to the cross section of the mould c.and. so on, and finally a casting is produced having various crosssections f, e, d, a, each cross section extending over any desiredlength of the casting.

In this method of casting the nozzle a is constantly located with itsend b at a fixed point. However, the method may also be such that inaddition to the downward movement of the mould the nozzle issimultaneously moved in the opposite direction, i. e. upwardly, thusefiecting a more rapid transition from one cross section to liquid head.As soon as a suflicient length of casting'having the cross section f hasbeen obtained, the nozzle is withdrawn upwardly until I it. is againjust within the liquid head in the mould e after the mould f has beenremoved, for exampleto the point marked l. During the upward movement ofthe nozzle or alternatively when the latter has reached point I, themould f is removed downwardly. As in the meantime the spacecorresponding to the bevelling has been filled with molten mass and thishas solidified, the solidified end downwardly moving casting pushes themould f in the downward direction as soon as the devices retaining saidmould have been released. The same method is followed in the case of themoulds e, d and c, the nozzle being raised in the meantime first topoint 2, then to point 3 and so on upwardly.

According to Figure 2 means are provided for casting a casting havingvarious cross sections arranged in steps, consisting of one single mouldthe internal wall of which possesses the cross sections to be cast. Theinternal wall of the cooled mould c is divided into a number of crosssections dq. The height of each individual cross section is soproportioned as to always be slightly larger than the appertainingliquid head, so as to ensure satisfactory casting and solidifying.

The casting process according to this embodiment is as follows:

The nozzle a is located with its lower end b in the largest crosssection at so that the nozzle end b is constantly located within theliquid head having the cross section d. The casting process is continuedwith this cross section until the desired length of casting has beenreached. The end b of the nozzle a is then raised so far into the crosssection e that it is located just within the liquid head in the lattercross section. Casting is then carried on in this cross section untilthe desired length of casting has been obtained, whereupon the end b ofthe nozzle is raised into the next cross section 1. The process iscontinued until casting has taken place in all the cross sections forthe required lengths so that finally the end b of the nozzle (1 islocated in the cross section q.

The same result can of course be obtained when the nozzle a isstationary and the mould c is moved downwardly according to the lengthrequired for each different cross section.

As a further alternative, both the nozzle and the mould may be movedsimultaneously in opposite directions.

In the hereinbefore described devices illustrated in Figures 1 and 2,the transition from one cross section to another is efiected step bystep at intervals and consequently a casting is produced having crosssections; which vary step by step.

The arrangement according to Figure 3 now proceeds from the step by stepcasting method to the casting of conical castings. Also in this case isthe cooled mould, having internal surfaces tapering toward the top. Thelength of the wall of the mould and the conicity correspond to the ratioof length to the conicity of the casting s to be produced. The shape ofthe interior of the mould thus corresponds to a smaller scale of theshape of the casting to be produced. The casting process is as follows:

The nozzle :1 is at first located with its end b in the cylindrical orrectangular portion of the cross-section of the mould c. The mould isfilled and the plant is set in motion as soon as the end b is within theliquid head in the cylindrical or rectangular portion. At the same timea mechanism is set-in motion for raising the nozzle upwardly at apre-determined speed. The operator in attention must take care duringthe whole of the casting process to see that the end b of the nozzleremains at a constant level within the liquid head. The conical castingis thus automatically produced, the length and conicity of which dependsupon the speed at which the nozzle is raised. The greater the speed thegreater will be the conicity and the shorter will be the casting, andvice-versa.

It is understood that the upward movement of the nozzle can also bearrested for a certain period during the casting, so that during thisperiod there will be produced a portion of casting which is not conical.As soon as the nozzle is again set in motion the shape of the castingwill again be made conical. The same result can be obtained when thenozzle is stationary and the mould is moved or when both nozzle andmould are moved simultaneously. The movement of the mould and of thenozzle is best eflected automatically by the aid of well knownmechanical means.

In these processes it is also possible to cast in the reversed sequence,for example in such a manner that when the nozzle a reaches itsuppermost position the process can be continued by slowly moving thenozzle downwardly again. In this manner a casting is produced which isconically tapering towards both ends.

In many continuous casting processes the mould carries out in additionan up and down movement in order that a uniform structure may beobtained in the casting. For this purpose the arrangements according toFigures 1 and 2 but not the arrangement in Figure 3, are suitable.During this continuous up and down movement of the mould the infiowingliquid metal would flow between the solidified endless casting and thewall of the mould.

In such cases where a reciprocatory movement is required the castingprocess must be carried out with the aid of an arrangement according toFigure 4. The process itself is the same as in the case of the deviceaccording to Figure 3 with the exception that the interior wall of themould c is so arranged that the necessary to and fro movement is notefiected in the direction indicated by the arrow :1: but in thedirection of the arrow y. This to and fro movement is effected by meansof plates arranged adjacent the wall of the mould.

By the aid of the device according to Figure 5 castings are producedwhich are vertical on one side and have a conical surface of the otherside (with respect to the direction of feed of the endless castings). Inthis case two castings are produced simultaneously; a and a are the twonozzles havingthe lower ends I) and D The outer cooled mould havingplane inner walls is designated by the letter 0 whilst d is the innermould having the conical outer walls. e is the water inlet pipe for theinner mould d.

The casting process is the same aswith the device .in Figure 3. Theouter ;muld can in this case be moved to and fro during the castingprocess whilst the inner mould must remain stationary. When however anup and down movement of the inner mould d is also required the outerwalls of the said inner mould' (1 must be arranged so as to be movablein the direction of the arrow y as in the process according to Figure 4and the device as in'Figure 6. The casting process is then carried outin the manner described with reference to the device according to Figure3.

The processes described with reference to Figures 1 to 6 illustrate byway of example a few methods and means for obtaining in a continuousworking operation castings having different cross sections.

It is of course possible to produce not only the cross sectionsillustrated in the drawing and described in the foregoing but alsoentirely different cross sections in one and the same casting, forexample the casting may have a circular cross section which goes overinto a rectangular or square or hexagonal cross section.

The methods and devices described are intended to show merely theprinciples on which various cross sections can be obtained in acontinuous process in one and the same casting. The invention of coursecomprises all possible constructional forms which fall within theprinciples disclosed.

Having now particularly described andascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. A mold for continuous string casting, comprising an open endedcasting mold having its inner. wall enclosing a hollow chamberdecreasing materially in size from the bottom to the top, and a tubeextending into the mold to convey the metal therein and being movable inthe direction of the axis of the mold in relation to the mold.

2. A mold for continuous string casting, comprising an open endedcasting mold having its inner wall enclosing the hollow chamberdecreasing in size from the bottom to the top, a tube extending into themold to convey the metal therein, and plates arranged adjacent the innerwall of the mold which are movable along the inner wall.

3. A method for casting continuously produced cast articles whose crosssection at various planes of the article have different diameters,comprising applying a molten metal to an open-ended mold, the internalwall of which is formed as step like deposits whereby the step of largerdiameter is arranged the lowest in the mold, maintaining the height ofthe upper surface of the cast metal constant in the mold during thecasting of each particular diameter, and raising this upper surfacestep-wise when the diameter of the casting is to be altered.

4. A method of continuous string casting having varying cross sectionsat different places, comprising introducing a molten metal by means of atube into an open-ended mold which at various planes along its heighthas various cross sections, which decrease from the bottomto the top,maintaining the height of the upper surface of the cast metal relativeto the mold constant during the casting of each cross sectionalconfiguration, casting the metal and changing the height of the uppersurface of the metal relative to the mold as soon as one casting is tobe cast into another cross section.

5. A method of continuous stringcasting having varying cross sections atdifferent places, comprising introducing a molten metal by means of atube into an open-ended mold which at various planes along its heighthas various cross sections, which decrease from the bottom to the top,and continuously changing, the height of the upper surface of the castmetal relative to the mold from the bottom to the top of each crosssectional configuration.

6. A method for casing continuously produced cast articles whose crosssection at various planes of the article have different diameters,comprising applying a molten metal to an openended mold, the internalwall of which is formed as step like deposits whereby the step of largerdiameter 'is arranged the lowest in the mold, maintaining the height ofthe upper surface of the cast metal constant in the mold during thecasting of each particular diameter, and raising this upper surfacecontinuously when the diameter of thecasting is to be altered.

7. A mould for continuous string casting, comprising an open endedcasting mold having its inner wall shaped as stepped sections each ofthe sections having a materially larger diameter than the section aboveit, and a tube extending into the mold to convey the metal therein, andbeing movable in the direction of the axis of the mold in relation tothe mold.

8. A mold for continuous string casting, comprising an open endedcasting mold having its inner wall enclosing a hollow chamber decreasingmaterially in size from the bottom to the top, and a tube extending intothe mold to convey the metal therein, said tube and mold being movablerelative to each other.

9. A method according to claim 3, in which the rais'ng of the uppersurface of the cast metal when the diameter of the casting is to bealtered,

is carried out by increasing the flow of the molten metal above thatwhich is required to produce the casting.

10. A method according to claim 4, in which lower outlet opening of thetube is maintained at a constant distance below the level of the uppersurface of the cast metal.

TSIEGFRIED JUNGHANS.

